bmt437-introduction to control systems

7/31/2019 Bmt437-Introduction to Control Systems

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Course Overview:

Biological Control System BMT 437


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COURSE SYNOPSIS

Provides a background of control principles invarious engineering applications. Basicmathematical tools such as Laplace transform,

transfer function, block diagram, signal flowgraph, mathematical modeling of dynamicsystems, time response analysis, stability oflinear system, root locus and frequency domainanalysis are utilized.


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COURSE EVALUATION

Final Examination : 40%

Lab Assessment : 20%

1st & 2nd Mid-Term : 30%

Assignments : 10%

Total Mark : 100%


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LIST OF REFERENCES

Textbook

i. Nise N.S. (2004). Control System Engineering (4th Ed), JohnWiley & Sons.

References

ii. Ogata K. (2002). Modern Control Engineering (4th Ed),Prentice Hall.

iii. Dorf R.C., Bishop R.H. (2001). Modern Control Systems (9th

Ed), Prentice Hall.


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ACADEMIC STAFF MEMBERS

Lecturer

Dr. Mohd Rizon Mohamed Juhari

B.Eng (Japan), M.Eng (Japan), Dr.Eng (Japan)

Engineer

Eng. Emad Amin Mohamed


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TEACHING PLAN

Week Course Content

1-2 Introduction to Control Systems

3-4 The Basics of Control Theory

5-6 Mathematical Model of Systems

7-9 System Stability

10-11 Time-Domain Analysis

12-13 The Root Locus Method

14 Frequency Response Method

15 Controller


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LAB SESSIONS

Lab Title

1 Introduction to MatLab Simulink

2 Open-loop System Characteristics

3 Closed-loop System Characteristics

4 Study of Time-Response for 1st OrderSystems

5 Study of Open-loop System Models

6 Study of Closed-loop System Models.


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Introduction to Control Systems:

Biological Control System BMT 437


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CONTENTS

Basic Concepts

Control System Examples

Control System Design


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BASIC CONCEPTS

System

A collection of components which are coordinated together toperform a function.

Dynamic System

A system with a memory.

For example, the input value at time t will influence the outputat future instant.

A system interact with their environment through a

controlled boundary.


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BASIC CONCEPTS

The interaction is defined in terms of variables.

i. System input

ii. System output

iii. Environmental disturbances


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SYSTEM VARIABLES

The systems boundary depends upon the defined objectivefunction of the system.

The systems function is expressed in terms ofmeasuredoutput variables.

The systems operation is manipulated through control inputvariables.

The systems operation is also affected in an uncontrolled

manner through disturbance input variables.


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CONTROL SYSTEM

Control is the process of causing a system variable toconform to some desired value.

Manualcontrol Automatic control (involving machinesonly).

A control system is an interconnection of componentsforming a system configuration that will provide a desiredsystem response.

ControlSystem

Output

Signal

Input

Signal

EnergySource


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MANUAL VS AUTOMATIC CONTROL

Control is a process of causing a system variable such astemperature or position to conform to some desired value ortrajectory, called reference value or trajectory.

For example, driving a car implies controlling the vehicle to

follow the desired path to arrive safely at a planneddestination.

i. If you are driving the car yourself, you are performing manualcontrol of the car.

ii. If you use design a machine, or use a computer to do it, then youhave built an automatic control system.


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RESPONSE CHARACTERISTICS

Transient response: Gradual change of output from initial to the desired condition

Steady-state response:

Approximation to the desired response

For example, consider an elevator rising from ground to the4th floor.


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BLOCK DIAGRAM

Component or process to be controlled can be represented by ablock diagram.

The input-output relationship represents the cause and effect ofthe process.

Control systems can be classified into two categories:

i. Open-loop control systemii. Closed-loop feedback control system

Process OutputInput


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CONTROL SYSTEM CLASSIFICATION

An open-loop control system utilizes an actuating device tocontrol the process directly without using feedback.

A closed-loop feedback control system uses a measurement ofthe output and feedback of the output signal to compare it withthe desired output or reference.

ActuatingDevice

Process OutputDesired Output

Response

Desired

OutputRespons

e

Measurement

OutputController ProcessComparison

Single Input Single Output (SISO) System


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Open-Loop Control System

Missile Launcher System


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Closed-Loop Feedback Control System

Missile Launcher System


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DesiredOutput

Response

Measurement

OutputVariable

s

Controller Process

Multi Input Multi Output (MIMO) System


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PURPOSE OF CONTROL SYSTEMS

i. Power Amplification (Gain)

Positioning of a large radar antenna by low-power rotation of aknob

ii. Remote Control

Robotic arm used to pick up radioactive materials

iii. Convenience of Input Form

Changing room temperature by thermostat position

iv. Compensation for Disturbances

Controlling antenna position in the presence of large winddisturbance torque


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HISTORICAL DEVELOPMENTS

i. Ancient Greece (1 to 300 BC)

Water float regulation, water clock, automatic oil lamp

ii. Cornellis Drebbel (17th century)

Temperature control

iii. James Watt (18th century)

Flyball governor

iv. Late 19th to mid 20th century

Modern control theory


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WATTS FLYBALL GOVERNOR


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HUMAN SYSTEM

The Vetruvian Man


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HUMAN SYSTEM

i. Pancreas Regulates blood glucose level

ii. Adrenaline

Automatically generated to increase the heart rate and oxygen

in times of flightiii. Eye

Follow moving object

iv. Hand

Pick up an object and place it at a predetermined location

v. Temperature

Regulated temperature of 36C to 37C


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TEMPERATURE CONTROL

Figure shows a schematic diagram of temperature control of an electric

furnace. The temperature in the electric furnace is measured by athermometer, which is analog device. The analog temperature is convertedto a digital temperature by an A/D converter. The digital temperature is fedto a controller through an interface. This digital temperature is comparedwith the programmed input temperature, and if there is any error , thecontroller sends out a signal to the heater, through an interface, amplifier

and relay to bring the furnace temperature to a desired value.


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TRANSPORTATION

Car and Driver

Objective: To control direction and speed of car

Outputs: Actual direction and speed of car

Control inputs: Road markings and speed signs Disturbances: Road surface and grade, wind, obstacles

Possible subsystems: The car alone, power steering system,breaking system


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TRANSPORTATION

Functional block diagram:

Time response:

Measurement, visual and tactile

SteeringMechanism

AutomobileDriver

Desiredcourse

of travel

Actualcourse

of travelError+

-


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Consider using a radar to measure distance and velocity toautonomously maintain distance between vehicles.

Automotive: Engine regulation, active suspension, anti-lockbreaking system (ABS)

Steering of missiles, planes, aircraft and ships at sear.

TRANSPORTATION


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PROCESS INDUSTRY

Control used to regulate level, pressure and pressure of refineryvessel.

For steel rolling mills, the position of rolls is controlled by thethickness of the steel coming off the finishing line.

Coordinatedcontrol systemfor a boiler-generator.


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MANUFACTURING INDUSTRY

Consider a three-axis control system for inspecting individualsemiconducting wafers with a highly sensitive camera


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HOMES

i. CD Players

The position of the laser spot in relation to the microscopicpits in a CD is controlled.

ii. Air-Conditioning System

Uses thermostat and controls room temperature.


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CONTROL SYSTEM COMPONENTS

i. System, plant or process

To be controlled

ii. Actuators

Converts the control signal to a power signal

iii. Sensors

Provides measurement of the system output

iv. Reference input

Represents the desired output


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GENERAL CONTROL SYSTEM

Sensor

Actuator ProcessController ++

Set-pointor

Referenceinput

ActualOutput

ErrorControlled Signal

Disturbance

Manipulated Variable

Feedback Signal

+

-

++


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CONTROL SYSTEM DESIGN PROCESS

1. Establish control goals

2. Identify the variables to control

3. Write the specifications for the variables

4. Establish the system configuration and identify the actuator

5. Obtain a model of the process, the actuator and the sensor

6. Describe a controller and select key parameters to be adjusted

7. Optimize the parameters and analyze the performance

If the performance meet the specifications, then finalize design

If the performance doesnot meet specifications,then iterate the

configuration and actuator


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TURNTABLE SPEED CONTROL

Application: CD player, computer disk drive Requirement: Constant speed of rotation

Open loop control system:

Block diagram representation:


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TURNTABLE SPEED CONTROL

Closed-loop control system:

Block diagram representation:


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DISK DRIVE READ SYSTEM

Goal of the system: Position the reader head in order toread data stored on a track.

Variables to control: Position of the reader head


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DISK DRIVE READ SYSTEM

Specification:

i. Speed of disk: 1800 rpm to 7200 rpm

ii. Distance head-disk: Less than 100nm

iii. Position accuracy: 1 m

iv. Move the head from track a to track b within 50ms

System Configuration:


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ASSIGNMENT 1

Describe the principle of operation for Watts

Flyball Governor. Include the relevant blockdiagram and indicate the functional

components of the system. Your report should be no more than 2 pages

long.

The report should be submitted onWednesday (21/10/2000) during the tutorialsession.


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FURTHER READING

Chapter 1

i. Nise N.S. (2004). Control System Engineering (4th Ed), JohnWiley & Sons.

ii. Dorf R.C., Bishop R.H. (2001). Modern Control Systems (9th

Ed), Prentice Hall.


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THE END

The right half of the brain controls the left half of the body.

This means that only left handed people are in their rightmind

bmt437-introduction to control systems

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